The present invention relates to a level regulating system for use with automotive vehicles of the type including a hydraulically operated level adjusting device located on at least one axle of the automotive vehicle, and a fluid separator comprising a hydraulic cylinder wherein at least one inlet pressure chamber is separated from at least one outlet pressure chamber by a hydraulic piston to which a restoring force acting in opposition to the pressure in the inlet pressure chamber is applied. The outlet pressure chamber is capable of being connected to the level adjusting device and the inlet pressure chamber which is normally in communication with a hydraulic fluid return reservoir is, through switching valves, put temporarily in communication with a hydraulic pressure source for a primary user of hydraulic pressure, such as a brake system of the automotive vehicle.
In level regulating systems for automotive vehicles of this type, a hydraulic pressure source provided in the automotive vehicle, e.g., a brake pressure source of a hydraulic brake force booster, is used for providing both the hydraulic pressure required for energizing a brake and during periods in which no braking is effected, for level control, wherein the pressure supplied by the brake or hydraulic pressure source, through a fluid separator, is passed on to the level adjusting device. For this purpose, a chamber adapted to the volume of the level adjusting means is required for the input and output pressure chamber in the hydraulic cylinder of the fluid separator. In addition, with the same transmission ratio, another space of equal volume is required to prevent the sealants from coming into contact with the surface wetted by the respectively other hydraulic fluid.
It is conventional to increase the pressure in the level adjusting means gradually rather than in one step so that the pressure chambers of the fluid separator do not have to have the entire volume of the level adjusting means. Although the space requirement of the fluid separator and the weight thereof can be reduced thereby, it is not always possible by simple means to adapt an existing hydraulic pressure source to the requirements of the level adjusting means.